Lets do my first B12 injection together This is something Ive been nervous about for a long time, but today I finally did itand it honestly wasnt bad at all. I used the Union Medico needle guide Vitamin B12 Injections: Hot Shots? Full Guide PA Relief Taking Vitamin B12? Read this first. While B12 is often hailed as a safe energy and brain booster, many real users are reporting unexpected side effects including anxiety, insomnia, GoTox RevIVe Ever wonder how fast you'll feel that B12 kick in? After an IM B12 injection, most people feel results in 1248 hours sometimes even Instagram How Quickly Does B12 Shot Work? Duration of Benefits Vitamin B12 Injections